About 4 years ago, I obtained a fairly pristine Columbia Sports 3. While a bit of a limp noodle of a frame, the fit was much to my liking, and I set about upgrading it in various ways; I converted the bottom bracket to facilitate using a modern 3 piece crank, and obtained nice wheels from Harris Cyclery to replaced the chromed steel ones. Latter were heavy, and very frightening when wet. Anyway, the replacement rear wheel had the S-RF3 hub, which seems to be generally regarded as a worthy successor to the AW. With the grease, rather than oil lube, no leakage, and no false neutral possible from a bum cable adjustment, either.

After about 3 years and 3000 miles, I was noticing that the shifting was not so easy anymore, and more irksome, when downshifting to first, there would intermittently be a "CLUNK", like a bad ratchet tooth, or maybe sticky pawls. I decided to do a tear-down and flush, and convert to some sort of liquid lubrication. At this point, I'll publicly thank FBinNY for much wise counsel and patience in answering questions I had about suitable lubricant, and Dan Burkhart for his posts here, and You Tube tutorials on internal gear hubs. I was a bit apprehensive about doing a full disassembly, thinking that maybe if I just got the inner assembly out, sloshed it in a coffee can full of kerosene, blew out, and drowned it Chain-L,
and repacked the ball ring and outer bearings with grease, that would suffice. But, as I dug in, the overall good condition made me worry about what the clunk could be. So- I dug in, and found that one of the low gear pawl springs was not on the pin at all! It was just sort of floating beside the pawl. It had to have been thus from day one. There was no visible damage, and I was able to put the pawl in properly. I did do the kerosene slosh, old paintbrush and blowgun treatment to all the parts, and reassembled with marine grease in the bearings, and 2 teaspoons of Dexron ATF in the body. (Sorry, Francis- I wanted to save the Chain-L for the chain, and felt something a little lighter might be better for Indianapolis winter temperatures.) Anyway, it spins and shifts better in the work stand than ever. It was getting dark, and I had replaced the chain and cog, and want to let the Chain-L penetrate well before wiping down and riding. So- no test ride tonight, but I'm confident it will be fine.

Wow... this is getting too long! Anyway, I guess where I am going with the post is:
1. New Sturmey Archer 3 speed hubs are sturdy! Running just one pawl for low, for thousands of miles, didn't seem to damage the ratchet teeth, or anything else.

2. The S-RF3 overhaul is really easier done than said. The exploded views from the factory technical information are a bit daunting, but when one has one on the work bench, the way the bits go together are fairly obvious. The pawls might be a bit tricky (obviously, the factory didn't even get mine right!) but if one is attentive, does one at a time while saving the other side for reference, etc. it is very serviceable.

Thanks to FBinNY, Dan Burkhart, noglider, and Sixty-Fiver for the storehouse of information here! Doing a detail strip, finding the problem and getting the hub back together and working silky smooth is a great feeling of accomplishment. The S-RF3 is NOT actually a Rubix Cube of hubs.

Update- Have had the hub back in action for about a week now. And- still have a highly intermittent clunk in low gear. There MUST be a damaged tooth the low gear pawls skip out of, that I missed. But, the hub is entirely rideable as is, and the shifting and ticking sounds are much nicer with the innards cleaned and lubed. At this point, I am just going to ride it until it either bombs, or is due for another major teardown, inspection, etc.

So much for my delusions of adequacy on a resolution of the clunk. Digging in to the NIG S/A has been rewarding in itself.

I know this post is a few months old, but I just fixed the same problem with one of my S-RF3 hubs. Mine would clunk in low gear. I could hear it and feel it through the pedals. The clunking hub did it since I got it.

Based on Sturmey Archer's technical information PDF file for the S-RF3, The low gear pawls are HSA 573, pawl for planet cage. The spring for both pawls is the HSA 435 circlip. I compared my good hub with the clunking hub. The pawls were identical, and undamaged, in both hubs. The same goes for the circlip in each hub. I noticed that the pawls on the clunking hub did not spring out as far. They sprang out about 8 mm on the good hub, but only 6.5 mm on the clunking hub. I removed the circlip from each hub, and discovered that the one on the clunking hub was flipped over. The circlip is not completely symmetrical. I flipped it back over to match the good hub and remeasured how far the pawls spring out. Now, the pawls on both hubs spring out 8 mm. This completely solved my clunking problem in low gear.

Thanks for the guidance on the flipped circlip. Subtle, intermittent problems are the worst. That sounds like something that I would have missed, and lacking a good hub to compare with, I was lost. I have dabbled with old AW hubs, but this is my first S-RF3. It seems like a very traditional Sturmey Archer, even with dodgy factory assembly, and in the case of mine, an inexperienced mechanic, they just keep working. Very over-engineered! It will probably not suffer too much if I defer the circlip check to the next tear-down and relube.

As an aside, I recently got a complete wheel with Nexus-3 coaster brake hub, and have reworked an old Schwinn World to be a 3 speed. It is apples and oranges comparing the drop-bar World with the old Columbia Sport-3 that I have the S-RF3 on, but the wider ratio of the Nexus works well for the drop-bar bike. Either bicycle works well for commuting around Indianapolis. Time will tell if the Nexus-3 gives as good service as the S-RF3 has. It is kind of nice having an internal brake that maintains the same response in rainy conditions as dry. The coaster isn't great, but is better than I expected.

Thanks again for the follow up post. Shared experience is a great aspect of these forums.